Ever found yourself confronted with an inbox overflowing with general
messages that you can ignore and messages that you and only you can
act on? Here’s something to help you sort the wheat from the chaff.

This indicates how personal messages are so you can immediately see which messages are just for you and which are part of a long Cc. Stephen Perelgut showed me the feature in Lotus Notes and I wanted to steal it sometime, so I did it while waiting for the Instant Rails archive.